This application is based on Application No. 2000-163753 filed in Japan, the contents of which are incorporated herein by reference.
1. Field of the Invention
The present invention relates to a heating cooker and, more particularly, to a microwave oven. The invention further relates to a switch control device and method to be employed in such a heating cooker.
2. Description of Related Art
Hitherto known as a switch for use in a microwave oven is a combination switch which functions as a push switch for outputting a cooking start signal in response to depression of the switch and as a rotary switch for outputting a cooking period signal according to the amount of turning of the switch.
The known switch for the microwave oven has two functions and, therefore, is contributable to an easy-to-handle design of the microwave oven with a reduced number of switches. However, the switch has drawbacks with a tendency toward the following misoperations due to its two functions as the push switch and as the rotary switch.
When a user depresses the switch to start a cooking operation after having set a cooking period by turning the switch, a misoperation of the switch is liable to occur with the switch inadvertently turned. Particularly, the user is liable to depress the switch while inadvertently turning the switch, whereby the cooking period once set is changed at the start of the cooking operation.
Further, the user may inadvertently depress the switch when turning the switch for the setting of the cooking period.
With either of the misoperations of the switch, over-heating or under-heating occurs because the cooking period is not set as intended by the user at the start of the cooking operation.
If the user becomes aware of the misoperations of the switch, the user may interrupt the cooking operation to reset the cooking period, but such a resetting operation is troublesome. Therefore, a switch is desired which requires no resetting operation.
In view of the foregoing, it is an object of the present invention to improve the operability of a depressible rotary switch for use in a heating cooker.
It is another object of the present invention to provide a switch control device and method which ensure an improved operability of a depressible rotary switch by rejecting an output signal generated due to a misoperation of the switch.
It is further another object of the present invention to improve the operability of a heating cooker having a depressible rotary switch.
In accordance with the present invention, there is provided a device for signal control of a switch which outputs a first signal in response to a turning operation thereof and outputs a second signal in response to a depressing operation thereof. If one of the first and second signals is outputted in response to a corresponding one of the switch turning operation and the switch depressing operation and the other signal is thereafter outputted in response to the other operation within a predetermined period, the control device nullifies the other signal.
With this arrangement, a heating cooker provided with the switch is prevented from performing an under-heat or over-heat cooking operation on the basis of a misoperation of the switch. Further, the need for resetting a cooking period is obviated, which may otherwise arise from the misoperation of the switch.
The foregoing and other objects, features and effects of the present invention will become more apparent from the following detailed description with reference to the attached drawings.